The present disclosure relates to semiconductor devices and, more particularly, to variable resistance memory devices. Semiconductor devices may include memory devices and logic devices. Memory devices may store data. In general, semiconductor memory devices can be broadly classified as volatile memory devices and nonvolatile memory devices. A volatile memory device, for example, DRAM (Dynamic Random Access Memory) and SRAM (Static Random Access Memory), is a memory device which loses stored data when its power supply is interrupted. A nonvolatile memory device, for example, PROM (programmable ROM), EPROM (erasable PROM), EEPROM (electrically EPROM), and Flash memory, is a memory device which does not lose stored data even when its power supply is inhibited.
Next generation semiconductor memory devices, including, for example, MRAM (magnetic random access memory) and PRAM (phase change random access memory) devices, have been developed to provide high performance and low power in semiconductor memory devices. The next generation semiconductor memory devices may include a material having a resistance that changes depending on applied electric current or voltage, and/or a resistance that is maintained even if the electric current or voltage supply is interrupted.